Problems with 2TB mybook essential USB 3.0 (Samsung TV)

Good day All

I need a bit of assistance.

Recently purchsed a 3TB My Book Essential USB3.0 External hard drive.

I have a Samsung 40" LCD TV model number LA40D550 with a built in media player.

Originally when I plugged it in, the device was not recognised by Samsung TV since the drive size was too large.

I then proceeded to partition the drive into 2TB and 800GB respectively.

The 2TB picks up on the tele as well as identifies all the files, and up to last night had no problem with playing mp4 files.

Recently had four mp4 files added to the HDD from my PC to watch and the Samsung says “Problem with the file, Invalid file”

Browse to other folders within the HDD, play a mp4, it works.

Plug the HDD into PC, check to see if the files were corrupt, No, plays perfectly.

Please help.

This question should be addressed to the media player manufacturer.